I remember something that happensed when I was an internt in a little town´s hospital a few years ago. I remember something that happened when I was an intern in a little town´s hospital a few years ago.

I remember something that happensed when I was an internt in a little town´s hospital a few years ago. I remember something that happened when I was an intern in a little town´s hospital a few years ago.

the "happen" was in the past, so the past tense is necessary.

In one of our shifts there we are four doctors. In one of our shifts there were four doctors.

In one of our shift, we arehad four doctors. In one of our shift, we had four doctors.

My partner and I takeook the first turn to rest, we wasere sleeping at the restroom aton the third floor since the 11:00 pm and we needed to go back to the ER at 3:00 am (that was the worst time to rest) but I don´t know why we don´t wake up at the correct time and go down ten minutes later. My partner and I took the first turn to rest, we were sleeping at the restroom on the third floor since 11:00 pm and we needed to go back to the ER at 3:00 am (that was the worst time to rest) but I don´t know why we don´t wake up at the correct time and go down ten minutes later.

My partner and I takeook the first turn to rest, we was. We had been sleeping atin the restroom aton the third floor since the 11:00 pm, and we needed to go back to the ER at 3:00 am (that. This was the worst time to rest) but. I don´t know why, but we doidn´t wake up at the correct time andto go down ten minutes later. My partner and I took the first turn to rest. We had been sleeping in the restroom on the third floor since 11:00 pm, and we needed to go back to the ER at 3:00 am. This was the worst time to rest. I don´t know why, but we didn´t wake up at the correct time to go down ten minutes later.

The "had been" construction is used here because you are referring to a past moment *within* the past tense.

IThe shift´s resident was in the team that had been waiting was the shift´s resident, and she was very angry. The shift´s resident was in the team that had been waiting, and she was very angry.

In tThe team that had been waiting was the shift´s resident,'s shift resident was waiting and she was very angry. The team's shift resident was waiting and she was very angry.

We were quite embarrassed and we apologized as soon as we arrived. We were quite embarrassed and we apologized as soon as we arrived.

We were quite embarrassed and we apologized as soon as we arrived. We were quite embarrassed and we apologized as soon as we arrived.

At the end of the every shift it is usual that the complete team hands over the shift to the next group of doctors, but my partner and I finished that day alone because our resident decided (in retaliation) not to go to ER to hand over the shift with us. At the end of the every shift it is usual that the complete team hands over the shift to the next group of doctors, but my partner and I finished that day alone because our resident decided (in retaliation) not to go to ER to hand over the shift with us.

At the end of the every shift, it is usual that the completwhole team hands over the shift to the next group of doctors, but. However, my partner and I finished that day alone because our resident decided (in retaliation) not to go toreturn to the ER to hand over the shift with us. At the end of the every shift, it is usual that the whole team hands over the shift to the next group of doctors. However, my partner and I finished that day alone because our resident decided (in retaliation) not to return to the ER to hand over the shift with us.